Directional drilling is a useful technique for several procedures such as utility installation, etc. One common type of directional drilling is horizontal directional drilling, where a drill stem is extended essentially horizontally to form passages under structures such as roads for example.
The drill stem typically includes multiple components, including a drill head, a sonde housing, sections of drill rod, etc. Drill heads in directional drilling typically have a feature which causes the drill head to steer in one direction when forced ahead by a drilling device. During a boring operation, pressure is applied through the drill stem from behind to the drill head. During a straight bore, the drill stem is typically rotated at a regular rate so that on average, only straight ahead drilling is accomplished. In order to steer a drill head, the rotation is temporarily stopped, and the drill head is allowed to steer in the desired direction. Once the steering maneuver is complete, the drill head is again rotated at a regular rate for straight ahead drilling.
Ground drilling requires large amounts of forward linear force, as well as large amounts of torque, applied to the drill stem. The drill stem also experiences frictional forces due to the interaction of the drill stem with the medium (i.e., soil, rock, sand, clay, etc.) through which the drill stem is traveling during a boring operation. Therefore, for a successful boring operation, it is necessary that the components, as well as the couplings therebetween, be able to withstand the various drilling forces without failure.
Various coupling designs and methods have been employed to connect drill stem components. One common method of connecting drill stem components is to threadingly couple one component to another, such that the linear and the rotational forces experienced during a drilling operation are transmitted from one component to the other through the threads of the adjoining components. Because of this, such threaded couplings are difficult to remove after the drilling operation is complete due to tightening of the threads during rotation of the drill stem in a drilling operation. Large tools, such as a pipe wrench, are frequently needed to disconnect the threaded-together drill stem components. Pipe wrenches or similar methods requiring large forces are inconvenient, and may be dangerous to the operator.
What is needed is a drill stem component connection system and method that provides structural integrity for drilling operations, while providing ease of assembly and disassembly with an increased level of safety.